Patent GB-733640-A (GB)
Title: Vehicle windscreen washers
Inventor: PARKES ERIC BERNARD
IPC: B60S1/48
Filed: 1952-10-15
Abstract: 733,640. Windscreen washers. LUCAS (INDUSTRIES), Ltd., J. Oct. 2, 1953 [Oct. 15, 1952; Nov. 17, 1952], Nos. 25811/52 and 28932/52. Class 138(1). A windscreen washer comprises a rotary pump, a liquid measuring chamber associated with the pump and adapted to contain the desired amount of liquid and to be supplied from a storage vessel, means for actuating the pump, and means dependent for its action on the presence of liquid in the chamber for automatically controlling the pump actuating means. In the embodiment of Fig. 1, the base f of the measuring chamber d forms the housing for a centrifugal pump impeller g. The chamber d is suspended from the cap b of the storage vessel a by a tube c through which passes the impeller spindle o driven by an electric motor p mounted on the cap b. Water in the vessel a can enter the chamber d through an orifice e at a rate which is small compared with the rate of discharge of water through an aperture h when the impeller is operating. When the motor is started by a manual switch q, the water in chamber d is discharged through a flexible tube i through a distensible capsule j, a flexible tube k and nozzle m on to the windscreen n. Expansion of the capsule operates a switch r in parallel with switch q to maintain the motor circuit when switch q is released. The chamber d communicates with atmosphere through the tube c and cap b has an air hole d. In a modified embodiment, Figs. 3, 3a (not shown), the retaining switch for the motor is operable by an arm fixed to the tube c which together with the measuring chamber and pump housing is rotated slightly by the torsional reaction of the impeller, against the action of a spring. Two other embodiments described with reference to Figs. 4 and 5 (not shown) differ from the previous embodiments in that only one switch controls the motor. The switch is normally held open by manually operable spring catch. A pivoted switch arm, having a contact coacting with a fixed contact, is movable in the case of the embodiment of Fig. 4 (not shown) by a rod connected to a float in the chamber d or in the case of the embodiment of Fig. 5 (not shown) by the tube c which is slidable vertically by the buoyancy of the mercury chamber, when empty. In another embodiment, Fig. 6 (not shown), the spindle o is operable by an air motor in communication with the suction in the engine inlet manifold or with a source of compressed air. The motor is operated by a manual valve and retained operating after release of the valve by a piston valve operable by the pressure of the discharging water. A further modification, Fig. 7 (not shown), includes an electromagnetic clutch between the spindle o and a flexible shaft connected with a source of power. A manual switch starts the washer operating and the clutch is thereafter maintained " made " by another parallel switch responsive to the pressure of the discharging water. Another embodiment, Fig. 2, differs from all the others in that the orifice e is dispensed with. The spindle o in this instance is connected by a sleeve o<SP>2</SP> to the spindle o<SP>1</SP> of the electric motor p. The underside of the impeller is provided with suitable radial grooves (not shown) so that when the impeller g is rotated it will lift axially to lift the sleeve 0 <SP>2</SP> and "make" a  motor retaining switch arm t. Axial play of the motor spindle permits this movement. The lower end of the spindle o has a peripheral groove so that when in its lower position, water in the vessel a can enter the chamber d through a filter y, passages r and the aperture h. When the spindle o is raised the passages r are cut off from communication with the vessel a. Specifications 467,950 and 672,190 are referred to.